First-order superconducting transition of investigated by magnetization and magnetic torque

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• 作者：Shunichiro Kittaka^a ; ^{kittaka@issp.u-tokyo.ac.jp" class="auth_mail" title="E-mail the corresponding author} ; Akira Kasahara^a ; Toshiro Sakakibara^a ; Daisuke Shibata^b ; Shingo Yonezawa^b ; Yoshiteru Maeno^b ; Kenichi Tenya^c ; Kazushige Machida^d
• 关键词：Sr2RuO4Sr2RuO4 ; Unconventional superconductivity ; First order ; Magnetization ; Magnetic torque
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：2016
• 出版时间：15 February 2016
• 年：2016
• 卷：400
• 期：Complete
• 页码：81-83
• 全文大小：463 K

文摘

The first-order superconducting transition, recently discovered in a long-standing candidate for a spin-triplet chiral-p  -wave superconductor Sr₂RuO₄${\mathrm{Sr}}_2{\mathrm{RuO}}_4$, is mysterious because it is not expected within the present scenario of spin-triplet superconductivity. To uncover its mechanism, we have measured the magnetization and the magnetic torque using an ultra-clean single crystal of Sr₂RuO₄${\mathrm{Sr}}_2{\mathrm{RuO}}_4$ down to 0.1 K. In this study, the magnetic-field orientation has been controlled with a high precision within the accuracy of 0.01°. We observed a sharp magnetization jump of as large as 0.01 emu/g with a field hysteresis of 100 Oe at 0.1 K. With increasing temperature, this magnetization jump decreases and diminishes above 0.8 K. The magnetic torque indicates that the first-order transition occurs only when the magnetic field is applied close to the ab   plane within 2 degrees deviation. These features of the first-order transition provide the keystone issues whose resolution is crucial in uncovering a “hidden” pair-breaking mechanism within the triplet-pairing scenario, or might urge the reconsideration of the order parameter in Sr₂RuO₄${\mathrm{Sr}}_2{\mathrm{RuO}}_4$.